Canada Street Cycle Bridge, Auckland

Key Project Details

Description

Client

Contractor

Project Value

$4 million. The project was jointly funded by the New Zealand Transport Agency and Auckland Council.

Duration

The project took only 14 months from concept to completion. The construction of the bridge was completed by the end of 2015.

Challenges

The complexity of the project was heightened by the unique design challenges presented by providing a structurally efficient bridge design, conforming to very tight site constraints while still providing a seamless curving structure.

A suitable construction sequence/methodology was derived to minimize traffic disruptions.

International design standards were adopted to facilitate and satisfy the design of a number of bridge elements.

Features

Steel orthotropic triangular deck

Diamond shaped piers that splay at the top to support in the inclined deck overhead

Challenging site constraints – Located at Central Motorway Junction in central Auckland

Landing one end of the bridge on the existing Nelson Street disused off-ramp

Architect

Monk Mackenzie

Steel Fabricators

PFS Engineering

Awards

Word Architecture Festival 2015

Finalist, with the winner to be announced in early November 2015.

The Canada Street Cycle Bridge is a spectacular realisation of the NZTA’s vision to provide world-class cycling infrastructure with this new cycle bridge built at Central Motorway Junction in central Auckland. This bridge provides a missing link in Auckland’s cycle network and provides a new seamless transition for cyclists between Newton Road (Upper Queen Street) and Union Street.

The superstructure is composed of a unique inverted triangular shaped steel orthotropic deck box girder. The bridge has a total length of 160m. The bridge curves from its landing on the existing Nelson Street off-ramp, spans over the Southbound lanes of SH1 and subsequently turns to weave its way alongside the Northern shoulder of SH1 to meet the bottom of Canada Street. The complex layout of the bridge was guided primarily by the fact that it has to function as a cycle bridge. As a result, due to tight site constraints it has to curve in plan in a number of locations to facilitate a smooth change of direction for cyclists, avoid site obstructions but also avoid encroaching over SH1.

Due to the curving nature of the bridge, a box girder type span was adopted due to its inherently efficient ability to deal with the effects of torsion. It proved to be the most efficient way of dealing with the in plan curvature and possible eccentric live loading on the bridge deck.

An architecturally striking triangular shape was adopted for the main pier located adjacent to SH1. This pier supports the main span of bridge as it crosses over SH1. A complex vertically tapering pier geometry was adopted in order to exhibit an effortless transition from the bridges superstructure to substructure.

The remaining bridge piers located on the North side of SH1 have a rhombic shape at the base. This shape transitions into a “splay” at the top of the pier in order cradle the deck overhead.

As the bridge spans one of the busiest sections of the NZ road network it was essential for Novare Design to devise a construction sequence/methodology that would minimise all traffic interruptions during the bridge construction. The selection of pre-fabricated bridge piers and deck segments made it possible to lift all elements of the bridge into place. It also restricts all road closures to night time while still maintaining an ambitious construction schedule.

Due to the unique shape of the deck, in-plan curvature and long length of the bridge, the bridge's complex dynamic behaviour was analysed using state-of-the-art finite element analysis software. This analysis investigated effects such as local distortion, warping stresses and out-of-plane stresses induced in the bridge deck due to the complex curvature. Dynamic time history analyses was also undertaken to investigate the behaviour of the bridge under pedestrian traffic loading.

About Novare Design

Novare Design is a New Zealand based company of civil and structural engineers providing superior service nationally and throughout Asia and the Pacific. We pair innovation with experience to provide a professional yet personalised service for our clients needs. Our expertise includes the buildings, bridges, civil and infrastructure sectors. Novare Design has gained an enviable reputation for delivering solutions that exceed our client's expectations.

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We provide local and international civil and structural design consultancy services to our clients, specialising in buildings, bridges, civil and infrastructure projects.

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